bFGF and JAGGED1 regulate alkaline phosphatase expression and mineralization in dental tissue-derived mesenchymal stem cells

Notch signaling regulates mineralization via microRNA modulation in dental pulp stem cells

OBJECTIVES

This study investigated the miRNA expression profile in Notch-activated human dental stem pulp stem cells (DPSCs) and validated the functions of miRNAs in modulating the odonto/osteogenic properties of DPSCs.

METHODS

DPSCs were treated with indirect immobilized Jagged1. The miRNA expression profile was examined using NanoString analysis. Bioinformatic analysis was performed, and miRNA expression was validated. Odonto/osteogenic differentiation was examined using alkaline phosphatase staining, Alizarin Red S staining, as well as odonto/osteogenic-related gene and protein expression.

RESULTS

Fourteen miRNAs were differentially expressed in Jagged1-treated DPSCs. Pathway analysis revealed that altered miRNAs were associated with TGF-β, Hippo, ErbB signalling pathways, FoxO and Ras signalling. Target prediction analysis demonstrated that 7604 genes were predicted to be targets for these altered miRNAs. Enrichment analysis revealed relationships to various DNA bindings. Among differentially expressed miRNA, miR-296-3p and miR-450b-5p were upregulated under Jagged1-treated conditions. Overexpression of miR-296-3p and miR-450b-5p enhanced mineralization and upregulation of odonto/osteogenic-related genes, whereas inhibition of these miRNAs revealed opposing results. The miR-296-3p and miR-450b-5p inhibitors attenuated the effects of Jagged1-induced mineralization in DPSCs.

CONCLUSIONS

Jagged-1 promotes mineralization in DPSCs that are partially regulated by miRNA. The novel understanding of these miRNAs could lead to innovative controlled mechanisms that can be applied to modulate biology-targeted dental materials.

IL-7-Treated Periodontal Ligament Cells Regulate Local Immune Homeostasis by Modulating Treg/Th17 Cell Polarization

Both interleukin (IL)-7 and human periodontal ligament cells (hPDLCs) have immunomodulatory properties. However, their combined effect on CD4⁺T cells has never been studied. In this study, we aimed to investigate the effect of conditioned medium of hPDLCs treated with rhIL-7 on the differentiation of CD4⁺T cells into regulatory T cells/T helper 17 cells (Treg/Th17 cells) and observe the effect of IL-7 on the immunomodulatory properties of PDLCs. After hPDLCs were treated with different concentrations of rhIL-7 for 24 h, the collected supernatants were used to incubate CD4⁺T cells for 3 days. A gamma-secretase inhibitor (DAPT) was used to suppress the activation of the Notch1 signaling pathway. Cell proliferation, apoptosis, and necrosis were determined using the cell counting kit-8 (CCK-8) and flow cytometry (FCM). The expressions of forkhead box P3 (Foxp3) in CD4⁺T cells and transforming growth factor (TGF-β) and IL-6 in the supernatants were determined by ELISA. Reverse transcription-quantitative PCR (RT-qPCR), and the Western blot (WB) determined the mRNA levels and protein expression of various target factors. FCM was used to detect the mean fluorescence intensity of PD-L1 in hPDLCs and to analyze the differentiation of Treg/Th17 cells. Our results showed that IL-7 promoted proliferation and inhibited apoptosis in hPDLCs, promoted the expression of TGF-β, PD-L1, Notch1, Jagged1, and Hes1, and inhibited the levels of hypoxia-inducible factor (HIF)-1α and TCF7, whereas the addition of DAPT effectively reversed these effects. Importantly, we found that the conditioned medium of hPDLCs treated with rhIL-7 promoted the polarization of CD4⁺T cells into Treg cells but had no significant effect on the differentiation of Th17 cells. Our study indicated that treatment of PDLCs with IL-7 can promote the polarization of CD4⁺T cells into Treg cells by modulating the expression of inflammatory factors and signaling molecules through activating the Notch1 signaling pathway, thus participating in the regulation of immune homeostasis in the periodontal microenvironment.

Engineering tissue morphogenesis: taking it up a Notch

Recreating functional tissues through bioengineering strategies requires steering of complex cell fate decisions. Notch, a juxtacrine signaling pathway, regulates cell fate and controls cellular organization with local precision. The engineering-friendly characteristics of the Notch pathway provide handles for engineering tissue patterning and morphogenesis. We discuss the physiological significance and mechanisms of Notch signaling with an emphasis on its potential use for engineering complex tissues. We highlight the current state of the art of Notch activation and provide a view on the design aspects, opportunities, and challenges in modulating Notch for tissue-engineering strategies. We propose that finely tuned control of Notch contributes to the generation of tissues with accurate form and functionality.

bFGF stimulated plasminogen activation factors, but inhibited alkaline phosphatase and SPARC in stem cells from apical Papilla: Involvement of MEK/ERK, TAK1 and p38 signaling

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bFGF induced uPA, uPAR, PAI-1 production/expression in SCAP →

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bFGF induced decline of ALP and SPARC of SCAP →

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The effects of bFGF are regulated by ERK, p38, TAK1 and Akt signaling →

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Crucial for SCAP proliferation, matrix turnover and differentiation →

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These events are important for revascularization/root apexogenesis

Introduction

Objectives

Methods

Results

Conclusion

Elements of 3D Bioprinting in Periodontal Regeneration: Frontiers and Prospects

Periodontitis is a chronic infectious disease worldwide, caused by the accumulation of bacterial plaque, which can lead to the destruction of periodontal supporting tissue and eventually tooth loss. The goal of periodontal treatment is to remove pathogenic factors and control the periodontal inflammation. However, the complete regeneration of periodontal supporting tissue is still a major challenge according to current technology. Tissue engineering recovers the injured tissue through seed cells, bio-capable scaffold and bioactive factors. Three-D-bioprinting is an emerging technology in regeneration medicine/tissue engineering, because of its high accuracy and high efficiency, providing a new strategy for periodontal regeneration. This article represents the materials of 3D bioprinting in periodontal regeneration from three aspects: oral seed cell, bio-scaffold and bio-active factors.

Polydatin Induces Differentiation and Radiation Sensitivity in Human Osteosarcoma Cells and Parallel Secretion through Lipid Metabolite Secretion

Osteosarcoma is a bone cancer characterized by the production of osteoid tissue and immature bone from mesenchymal cells. Osteosarcoma mainly affects long bones (femur is most frequently site) and occur in children and young adults with greater incidence. Here, we investigated the role accomplished by polydatin, a natural antioxidative compound, in promoting osteogenic differentiation alone or after radiation therapy on osteosarcoma cells. In vitro, polydatin significantly induced cell cycle arrest in S-phase and enhanced bone alkaline phosphatase activity. Moreover, the differentiation process was paralleled by the activation of Wnt-β-catenin pathway. In combination with radiotherapy, the pretreatment with polydatin promoted a radiosensitizing effect on osteosarcoma cancer cells as demonstrated by the upregulation of osteogenic markers and reduced clonogenic survival of tumor cells. Additionally, we analyzed, by mass spectrometry, the secretion of sphingolipid, ceramides, and their metabolites in osteosarcoma cells treated with polydatin. Overall, our results demonstrate that polydatin, through the secretion of sphingolipids and ceramide, induced osteogenic differentiation, alone and in the presence of ionizing therapy. Future investigations are needed to validate the use of polydatin in clinical practice as a potentiating agent of radiotherapy-induced anticancer effects.

Sinking Our Teeth in Getting Dental Stem Cells to Clinics for Bone Regeneration

Dental stem cells have been isolated from the medical waste of various dental tissues. They have been characterized by numerous markers, which are evaluated herein and differentiated into multiple cell types. They can also be used to generate cell lines and iPSCs for long-term in vitro research. Methods for utilizing these stem cells including cellular systems such as organoids or cell sheets, cell-free systems such as exosomes, and scaffold-based approaches with and without drug release concepts are reported in this review and presented with new pictures for clarification. These in vitro applications can be deployed in disease modeling and subsequent pharmaceutical research and also pave the way for tissue regeneration. The main focus herein is on the potential of dental stem cells for hard tissue regeneration, especially bone, by evaluating their potential for osteogenesis and angiogenesis, and the regulation of these two processes by growth factors and environmental stimulators. Current in vitro and in vivo publications show numerous benefits of using dental stem cells for research purposes and hard tissue regeneration. However, only a few clinical trials currently exist. The goal of this review is to pinpoint this imbalance and encourage scientists to pick up this research and proceed one step further to translation.

Interleukin 15 participates in Jagged1-induced mineralization in human dental pulp cells

OBJECTIVES

Crosstalk between Notch and other cell signaling molecules has been implicated to regulate the osteogenic differentiation. Understanding the interaction between Notch and IL15 is essential to reveal molecular mechanism. Thus, the objective of the present study was to investigate whether IL15 participates in the Notch signaling-induced mineral deposition in human dental pulp cells (hDPs).

METHODS

hDPs were explanted from dental pulp tissues. To activate Notch signaling, the cells were seeded on Jagged1-immobilized surfaces. The mRNA expression was evaluated using real-time polymerase chain reaction. hDPs were treated with 5-50 ng/mL IL15. Cell viability and proliferation were determined using an MTT assay. Mineral deposition was examined using alizarin red s and Von Kossa staining. In some experiments, the cells were pretreated with a JAK inhibitor prior to stimulation.

RESULTS

Jagged1 induced IL15 and IL15RA expression in hDPs. IL15 treatment significantly increased mineral deposition at 14 d and upregulated ALP, OCN, OSX, ANKH, and ENPP1 mRNA expression. IL15-induced mineralization was attenuated by JAK inhibitor pretreatment. Further, JAK inhibitor pretreatment inhibited the effect of Jagged1 on hDP mineral deposition.

CONCLUSION

IL15 promoted the osteogenic differentiation in hDPs. Moreover, IL15 participated in the Jagged1-induced mineralization in hDPs.

Modulating stemness of mesenchymal stem cells from exfoliated deciduous and permanent teeth by IL-17 and bFGF

Mesenchymal stem cells (MSCs) have been identified within dental pulp tissues of exfoliated deciduous (SHEDs) and permanent (DPSCs) teeth. Although differences in their proliferative and differentiation properties were revealed, variability in SHEDs and DPSCs responsiveness to growth factors and cytokines have not been studied before. Here, we investigated the influence of interleukin-17 (IL-17) and basic fibroblast growth factor (bFGF) on stemness features of SHEDs and DPSCs by analyzing their proliferation, clonogenicity, cell cycle progression, pluripotency markers expression and differentiation after 7-day treatment. Results indicated that IL-17 and bFGF differently affected SHEDs and DPSCs proliferation and clonogenicity, since bFGF increased proliferative and clonogenic potential of both cell types, while IL-17 similarly affected SHEDs, exerting no effects on adult counterparts DPSCs. In addition, both factors stimulated NANOG, OCT4, and SOX2 pluripotency markers expression in SHEDs and DPSCs showing diverse intracellular expression patterns dependent on MSCs type. As for the differentiation capacity, both factors displayed comparable effects on SHEDs and DPSCs, including stimulatory effect of IL-17 on early osteogenesis in contrast to the strong inhibitory effect showed for bFGF, while having no impact on SHEDs and DPSCs chondrogenesis. Moreover, bFGF combined with IL-17 reduced CD90 and stimulated CD73 expression on both types of MSCs, whereas each factor induced IL-6 expression indicating its' role in IL-17/bFGF-modulated properties of SHEDs and DPSCs. All these data demonstrated that dental pulp MSCs from primary and permanent teeth exert intrinsic features, providing novel evidence on how IL-17 and bFGF affect stem cell properties important for regeneration of dental pulp at different ages.

NOTCH2 participates in Jagged1-induced osteogenic differentiation in human periodontal ligament cells

Jagged1 activates Notch signaling and subsequently promotes osteogenic differentiation in human periodontal ligament cells (hPDLs). The present study investigated the participation of the Notch receptor, NOTCH2, in the Jagged1-induced osteogenic differentiation in hPDLs. NOTCH2 and NOTCH4 mRNA expression levels increased during hPDL osteogenic differentiation. However, the endogenous NOTCH2 expression levels were markedly higher compared with NOTCH4. NOTCH2 expression knockdown using shRNA in hPDLs did not dramatically alter their proliferation or osteogenic differentiation compared with the shRNA control. After seeding on Jagged1-immobilized surfaces and maintaining the hPDLs in osteogenic medium, HES1 and HEY1 mRNA levels were markedly reduced in the shNOTCH2-transduced cells compared with the shControl group. Further, shNOTCH2-transduced cells exhibited less alkaline phosphatase enzymatic activity and in vitro mineralization than the shControl cells when exposed to Jagged1. MSX2 and COL1A1 mRNA expression after Jagged1 activation were reduced in shNOTCH2-transduced cells. Endogenous Notch signaling inhibition using a γ-secretase inhibitor (DAPT) attenuated mineralization in hPDLs. DAPT treatment significantly promoted TWIST1, but decreased ALP, mRNA expression, compared with the control. In conclusion, Notch signaling is involved in hPDL osteogenic differentiation. Moreover, NOTCH2 participates in the mechanism by which Jagged1 induced osteogenic differentiation in hPDLs.

Transcriptome analysis of basic fibroblast growth factor treated stem cells isolated from human exfoliated deciduous teeth

Background

Basic fibroblast growth factor (bFGF) regulates cell proliferation, migration, and differentiation in various cell types. The aim of the present study was to determine the bFGF target genes in stem cells isolated from human exfoliated deciduous teeth (SHEDs).

Methods

Cells were isolated from pulp tissue obtained from exfoliated deciduous teeth. Mesenchymal stem cell surface markers and the differentiation potential toward adipogenic and neurogenic lineages were characterized. The bFGF-treated SHED transcriptome was examined using a high throughput RNA sequencing technique. The mRNA and protein expression of selected genes were evaluated using real-time polymerase chain reaction and immunofluorescence staining, respectively. Cell cycle analysis was performed by flow cytometry. The colony forming unit number was also examined.

Results

The isolated cells expressed CD44, CD90, CD105, but not CD45. The upregulation of adipogenic and neurogenic marker genes was observed after culturing cells in the appropriate induction medium. Transcriptome analysis of the bFGF treated cells revealed that the upregulated genes were in the cell cycle related pathways, while the downregulated genes were in the extracellular matrix related pathways. Correspondingly, bFGF induced MKI67 mRNA expression and Ki67 protein expression. Furthermore, bFGF treatment significantly decreased the G0/G1, but increased the G2/M, population in SHEDs. Colony formation was markedly increased in the bFGF treated group and was attenuated by pretreating the cells with FGFR or PI3K inhibitors.

Conclusion

bFGF controls cell cycle progression in SHEDs. Thus, it can be used to amplify cell number to obtain the amount of cells required for regenerative treatments.

Drug Delivery Systems Based on Titania Nanotubes and Active Agents for Enhanced Osseointegration of Bone Implants

TiO2 nanotubes (TNTs) are attractive nanostructures for localized drug delivery. Owing to their excellent biocompatibility and physicochemical properties, numerous functionalizations of TNTs have been attempted for their use as therapeutic agent delivery platforms. In this review, we discuss the current advances in the applications of TNT-based delivery systems with an emphasis on the various functionalizations of TNTs for enhancing osteogenesis at the bone-implant interface and for preventing implant-related infection. Innovation of therapies for enhancing osteogenesis still represents a critical challenge in regeneration of bone defects. The overall concept focuses on the use of osteoconductive materials in combination with the use of osteoinductive or osteopromotive factors. In this context, we highlight the strategies for improving the functionality of TNTs, using five classes of bioactive agents: growth factors (GFs), statins, plant derived molecules, inorganic therapeutic ions/nanoparticles (NPs) and antimicrobial compounds.

Bacterial cellulose membrane conjugated with plant-derived osteopontin: Preparation and its potential for bone tissue regeneration

Bacterial cellulose membrane (BCM) has been recently recognized as a new generation of carbohydrate-based nanomaterial that possesses a great potential in tissue engineering applications. This research aims to develop an active non-resorbable guided tissue regeneration (GTR) membrane from BCM by conjugating with plant-derived recombinant human osteopontin (p-rhOPN), an economically produced and RGD-containing biomolecule. The BCM was initially grafted with poly(acrylic acid) (PAA) brushes to form poly(acrylic acid)-grafted BCM. Multiple carboxyl groups introduced to the BCM by PAA can serve as active anchoring points for p-rhOPN conjugation and yielded p-rhOPN-BCM. All chemically modified BCMs were characterized by attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, while their surface morphology was evaluated by field emission-scanning electron microscopy and atomic force microscopy analyses. The amount of p-rhOPN adhered on the membrane was quantified by enzyme-linked immunosorbent assay. The immunocytochemistry, two-stage quantitative real-time reverse transcriptase polymerase chain reaction and in vitro mineralization analyses strongly suggested that p-rhOPN-BCM could elicit biological functions leading to the enhancement of osteogenic differentiation of human periodontal ligament stem cells as effective as BCM conjugated with commercially available rhOPN from mammalian cells (rhOPN-BCM), suggesting its potential to be used as GTR membrane to promote bone tissue regeneration.

Decreased osteogenic activity and mineralization of alveolar bone cells from a patient with amelogenesis imperfecta and FAM83H 1261G>T mutation

FAM83H mutations lead to autosomal dominant hypocalcified amelogenesis imperfecta (ADHCAI). However, the biological role of FAM83H remains unclear. The present study aimed to characterize the alveolar bone cells isolated from a patient with ADHCAI having the mutation, c.1261G > T, p.E421*, in FAM83H. We showed that FAM83H mutant cells had proliferation ability and morphology similar to the controls. The F-actin staining revealed that FAM83H mutant cells were remained in the earlier stages of cell spreading compared to the controls at 30 min, but their spreading was advanced comparable to the controls at later stages. After osteogenic induction, a significant decrease in mRNA levels of RUNX2 and ALP was observed in FAM83H mutant cells at day 7 compared with day 3 while their expressions were increased in the controls. The OPN levels in FAM83H mutant cells were not significantly changed at day 7 compared to day 3 while the controls showed a significant increase. After 14 days, the mineral deposition of FAM83H mutant cells was slightly lower than that of the controls. In conclusion, we identify that FAM83H bone cells have lower expression of osteogenic marker genes and mineralization while they maintain their morphology, proliferation, and spreading. Consistent with previous studies in the ameloblasts and periodontal ligamental cells, these evidences propose that FAM83H influences osteogenic differentiation across different cell types in oral cavity.

Gene expression profiling of Jagged1-treated human periodontal ligament cells

OBJECTIVE

Jagged1 regulates several biological functions in human periodontal ligament cells (hPDLs). The present study aimed to evaluate mRNA expression profiling of Jagged1-treated hPDLs using microarray technique.

METHODS

Notch ligands, Jagged1, were indirectly immobilized on tissue culture surface. Subsequently, hPDLs were seeded on Jagged1 immobilized surface and maintained in growth medium for 48 hr. Total RNA was collected and processed. Gene expression profiling was examined using microarray technique. Real-time polymerase chain reaction and immunofluorescence staining were employed to determine mRNA and protein expression levels, respectively. Cell proliferation and colony-forming unit assay were performed. Cell cycle was evaluated using propidium iodide staining and flow cytometry analysis.

RESULTS

The isolated cells demonstrated fibroblast-like morphology and exhibited the co-expression of CD44, CD90, and CD105 surface markers. After stimulated with Jagged1, the total of 411 genes was differentially expressed, consisting both coding and non-coding genes. For coding genes, 165 and 160 coding genes were upregulated and downregulated, respectively. Pathway analysis revealed that the upregulated genes were mainly involved in cellular interactions, signal transduction, and collagen formation and degradation while the downregulated genes were in the events and phases in cell cycle. Jagged1 significantly decreased cell proliferation, reduced colony-forming unit ability, and induced G0/G1 cell cycle arrest in hPDLs.

CONCLUSION

Jagged1 regulates various biological pathways in hPDLs. This gene expression profiling could help to understand the mechanisms potentially involved in the Notch signaling regulation in periodontal homeostasis.

Basic fibroblast growth factor regulates phosphate/pyrophosphate regulatory genes in stem cells isolated from human exfoliated deciduous teeth

Background

Basic fibroblast growth factor (bFGF) regulates maintenance of stemness and modulation of osteo/odontogenic differentiation and mineralization in stem cells from human exfoliated deciduous teeth (SHEDs). Mineralization in the bones and teeth is in part controlled by pericellular levels of inorganic phosphate (P_i), a component of hydroxyapatite, and inorganic pyrophosphate (PP_i), an inhibitor of mineralization. The progressive ankylosis protein (gene ANKH; protein ANKH) and ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1/ENPP1) increase PP_i and inhibit mineralization, while tissue-nonspecific alkaline phosphatase (ALPL; TNAP) is a critical pro-mineralization enzyme that hydrolyzes PP_i. We hypothesized that regulation by bFGF of mineralization in SHEDs occurs by modulation of P_i/PP_i-associated genes.

Methods

Cells were isolated from human exfoliated deciduous teeth and characterized for mesenchymal stem cell characteristics. Cells were treated with bFGF, and the osteogenic differentiation ability was determined. The mRNA expression was evaluated using real-time polymerase chain reaction. The mineralization was examined using alizarin red S staining.

Results

Cells isolated from primary teeth expressed mesenchymal stem cell markers, CD44, CD90, and CD105, and were able to differentiate into osteo/odontogenic and adipogenic lineages. Addition of 10 ng/ml bFGF to SHEDs during in vitro osteo/odontogenic differentiation decreased ALPL mRNA expression and ALP enzyme activity, increased ANKH mRNA, and decreased both P_i/PP_i ratio and mineral deposition. Effects of bFGF on ALPL and ANKH expression were detected within 24 h. Addition of 20 mM fibroblast growth factor receptor (FGFR) inhibitor SU5402 revealed the necessity of FGFR-mediated signaling, and inclusion of 1 μg/ml cyclohexamide (CHX) implicated the necessity of protein synthesis for effects on ALPL and ANKH. Addition of exogenous 10 μm PP_i inhibited mineralization and increased ANKH, collagen type 1a1 (COL1A1), and osteopontin (SPP1) mRNA, while addition of exogenous P_i increased mineralization and osterix (OSX), ANKH, SPP1, and dentin matrix protein 1 (DMP1) mRNA. The effects of PP_i and P_i on mineralization could be replicated by short-term 3- and 7-day treatments, suggesting signaling effects in addition to physicochemical regulation of mineral deposition.

Conclusion

This study reveals for the first time the effects of bFGF on P_i/PP_i regulators in SHEDs and implicates these factors in how bFGF directs osteo/odontogenic differentiation and mineralization by these cells.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-1093-9) contains supplementary material, which is available to authorized users.

Interleukin 6 promotes an in vitro mineral deposition by stem cells isolated from human exfoliated deciduous teeth

Interleukin 6 (IL-6) plays various roles including stem cell regulation. The present study investigated the effect of IL-6 on cell proliferation, colony forming unit ability, stem cell marker expression and differentiation ability in stem cells isolated from human exfoliated deciduous teeth (SHEDs). We reported that the isolated cells from dental pulp tissues for deciduous teeth expressed CD44, CD90 and CD105 but not CD45. These cells were able to differentiate into osteoblasts, adipocytes and neuronal-like cells. IL-6 treatment resulted in the significant increase of NANOG, SOX2 and REX1 mRNA expression. However, IL-6 had no effect on cell proliferation and colony forming unit ability. IL-6 did not alter adipogenic and neurogenic differentiation potency. IL-6 supplementation in osteogenic medium led to a significant increase of mineralization. Furthermore, IL-6 upregulated ALP, ANKH and PIT1 mRNA levels. In conclusion, IL-6 participates in the regulation of pluripotent marker expression and is also involved in mineralization process of SHEDs. Hence, IL-6 could be employed as a supplementary substance in culture medium to maintain stemness and to induce osteogenic induction in SHEDs for future regenerative cell therapy.

Indirect immobilized Jagged1 suppresses cell cycle progression and induces odonto/osteogenic differentiation in human dental pulp cells

Notch signaling regulates diverse biological processes in dental pulp tissue. The present study investigated the response of human dental pulp cells (hDPs) to the indirect immobilized Notch ligand Jagged1 in vitro. The indirect immobilized Jagged1 effectively activated Notch signaling in hDPs as confirmed by the upregulation of HES1 and HEY1 expression. Differential gene expression profiling using an RNA sequencing technique revealed that the indirect immobilized Jagged1 upregulated genes were mainly involved in extracellular matrix organization, disease, and signal transduction. Downregulated genes predominantly participated in the cell cycle, DNA replication, and DNA repair. Indirect immobilized Jagged1 significantly reduced cell proliferation, colony forming unit ability, and the number of cells in S phase. Jagged1 treated hDPs exhibited significantly higher ALP enzymatic activity, osteogenic marker gene expression, and mineralization compared with control. Pretreatment with a γ-secretase inhibitor attenuated the Jagged1-induced ALP activity and mineral deposition. NOTCH2 shRNA reduced the Jagged1-induced osteogenic marker gene expression, ALP enzymatic activity, and mineral deposition. In conclusion, indirect immobilized Jagged1 suppresses cell cycle progression and induces the odonto/osteogenic differentiation of hDPs via the canonical Notch signaling pathway.

Basic Fibroblast Growth Factor Regulates REX1 Expression Via IL-6 In Stem Cells Isolated From Human Exfoliated Deciduous Teeth

Basic fibroblast growth factor (bFGF) regulates pluripotent marker expression and cellular differentiation in various cell types. However, the mechanism by which bFGF regulates REX1 expression in stem cells, isolated from human exfoliated deciduous teeth (SHEDs) remains unclear. The aim of the present study was to investigate the regulation of REX1 expression by bFGF in SHEDs. SHEDs were isolated and characterized. Their mRNA and protein expression levels were determined using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. In some experiments, chemical inhibitors were added to the culture medium to impede specific signaling pathways. Cells isolated from human exfoliated deciduous tooth dental pulp tissue expressed mesenchymal stem cell surface markers (CD44, CD73, CD90, and CD105). These cells differentiated into osteogenic and adipogenic lineages, when appropriately induced. Treating SHEDs with bFGF induced REX1 mRNA expression and this effect was attenuated by pretreatment with FGFR or Akt inhibitors. Cycloheximide pretreatment also inhibited the bFGF-induced REX1 expression, implying the involvement of intermediate molecule(s). Further, the addition of an IL-6 neutralizing antibody attenuated the bFGF-induced REX1 expression by SHEDs. In conclusion, bFGF enhanced REX1 expression by SHEDs via the FGFR and Akt signaling pathways. Moreover, IL-6 participated in the bFGF-induced REX1 expression in SHEDs. J. Cell. Biochem. 118: 1480-1488, 2017. © 2016 Wiley Periodicals, Inc.

The Regulatory Effects of Long Noncoding RNA-ANCR on Dental Tissue-Derived Stem Cells

Long noncoding RNAs (lncRNA) have been recognized as important regulators in diverse biological processes, such as transcriptional regulation, stem cell proliferation, and differentiation. Previous study has demonstrated that lncRNA-ANCR (antidifferentiation ncRNA) plays a key role in regulating the proliferation and osteogenic differentiation of periodontal ligament stem cells (PDLSCs). However, little is known about the role of ANCR in regulating other types of dental tissue-derived stem cells (DTSCs) behaviours (including proliferation and multiple-potential of differentiation). In this study, we investigated the regulatory effects of lncRNA-ANCR on the proliferation and differentiation (including osteogenic, adipogenic, and neurogenic differentiation) of DTSCs, including dental pulp stem cells (DPSCs), PDLSCs, and stem cells from the apical papilla (SCAP) by downregulation of lncRNA-ANCR. We found that downregulation of ANCR exerted little effect on proliferation of DPSCs and SCAP but promoted the osteogenic, adipogenic, and neurogenic differentiation of DTSCs. These data provide an insight into the regulatory effects of long noncoding RNA-ANCR on DTSCs and indicate that ANCR is a very important regulatory factor in stem cell differentiation.

Serum and xeno-free, chemically defined, no-plate-coating-based culture system for mesenchymal stromal cells from the umbilical cord

OBJECTIVES

Umbilical cord mesenchymal stromal cells (UCMSCs) can be considered to become a new gold standard for MSC-based therapies. A serum and xeno-free, chemically defined and no-plate-coating-based culture system will greatly facilitate development of robust, clinically acceptable bioprocesses for reproducibly generating quality-assured UCMSCs.

MATERIALS AND METHODS

In this study, we report for the first time, such a serum-free, xeno-free, completely chemically defined and no-plate-coating-based culture system for the isolation and expansion of UCMSCs, whose biological characteristics were evaluated and compared with serum-containing medium (SCM) methods.

RESULTS

This culture system not only supported UCMSC primary cultures but also allowed for their expansion at low seeding density. Compared to SCM, UCMSCs in SFM exhibited (i) higher proliferative and colony-forming capacities; (ii) distinctly different morphologies; (iii) similar phenotype; (iv) similar pluripotency-associated marker expression; (v) superior osteogenic, but reduced adipogenic differentiation capacitities. In addition, UCMSCs cultured in SFM retained similar immunomodulatory properties to those in SCM.

CONCLUSIONS

Our findings demonstrate the feasibility of isolating and expanding UCMSCs in a completely serum-free, xeno-free, chemically defined and no-plate-coating-based culture system and represent an important step forward for development of robust, clinically acceptable bioprocesses for UCMSCs. Further, this provides a superior study platform for UCMSCs biology in a controlled environment.

M1 Macrophages Activate Notch Signalling in Epithelial Cells: Relevance in Crohn's Disease

BACKGROUND

The Notch signalling pathway plays an essential role in mucosal regeneration, which constitutes a key goal of Crohn's disease (CD) treatment. Macrophages coordinate tissue repair and several phenotypes have been reported which differ in the expression of surface proteins, cytokines and hypoxia-inducible factors (HIFs). We analysed the role of HIFs in the expression of Notch ligands in macrophages and the relevance of this pathway in mucosal regeneration.

METHODS

Human monocytes and U937-derived macrophages were polarized towards the M1 and M2 phenotypes and the expression levels of HIF-1α, HIF-2α, Jagged 1 (Jag1) and delta-like 4 (Dll4) were evaluated. The effects of macrophages on the expression of hairy and enhancer of split-1 (HES1, the main target of Notch signalling) and intestinal alkaline phosphatase (IAP, enterocyte marker) in epithelial cells in co-culture were also analysed. Phenotype macrophage markers and Notch signalling were evaluated in the mucosa of CD patients.

RESULTS

M1 macrophages were associated with HIF-1-dependent induction of Jag1 and Dll4, which increased HES1 protein levels and IAP activity in co-cultured epithelial cells. In the mucosa of CD patients a high percentage of M1 macrophages expressed both HIF-1α and Jag1 while M2 macrophages mainly expressed HIF-2α and we detected a good correlation between the ratio of M1/M2 macrophages and both HES1 and IAP protein levels.

CONCLUSION

M1, but not M2, macrophages are associated with HIF-1-dependent induction of Notch ligands and activation of epithelial Notch signalling pathway. In the mucosa of chronic CD patients, the prevalence of M2 macrophages is associated with diminution of Notch signalling and impaired enterocyte differentiation.

Effect of Jagged-1 and Dll-1 on osteogenic differentiation by stem cells from human exfoliated deciduous teeth

OBJECTIVE

The aim of the present study was to determine the influence of Notch ligands, Jagged-1 and Dll-1, on osteogenic differentiation by stem cells from human exfoliated deciduous teeth.

DESIGN

Notch ligands were immobilized on tissue culture surface using an indirect affinity immobilization technique. Cells from the remaining of dental pulp tissues from human deciduous teeth were isolated and characterized using flow cytometry and differentiation assay. Alkaline phosphatase (ALP) enzymatic activity, osteogenic marker gene expression, and mineralization were determined using ALP assay, real-time polymerase chain reaction, and alizarin red staining, respectively.

RESULTS

The isolated cells exhibited CD44, CD90, and CD105 expression but lack of CD45 expression. Further, these cells were able to differentiate toward osteogenic lineage. The upregulation of HES-1 and HEY-1 was observed in those cells on Dll-1 and Jagged-1 coated surface. The significant increase of ALP activity and mineralization was noted in those cells seeded on Jagged-1 surface and these results were attenuated when cells were pretreated with gamma secretase inhibitor. The significant upregulation of ALP and collagen type I gene expression was also observed in those cells seeded on Jagged-1 surface. The inconsistent Dll-1 induced osteogenic differentiation was found and high Dll-1 immobilized dose (50 nM) slightly enhanced alkaline phosphatase enzymatic activity. However, the statistical significant difference was not obtained as compared to the hFc control.

CONCLUSION

The surface immobilization of Notch ligands, Jagged-1 and Dll-1, likely to enhance osteogenic differentiation of SHEDs. However, Jagged-1 had more ability in enhancing osteogenic differentiation than Dll-1 in our model.

Epidermal growth factor enhances osteogenic differentiation of dental pulp stem cells in vitro

Introduction

Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) play an important role in extracellular matrix mineralization, a complex process required for proper bone regeneration, one of the biggest challenges in dentistry. The purpose of this study was to evaluate the osteogenic potential of EGF and bFGF on dental pulp stem cells (DPSCs).

Material and methods

Human DPSCs were isolated using CD105 magnetic microbeads and characterized by flow cytometry. To induce osteoblast differentiation, the cells were cultured in osteogenic medium supplemented with EGF or bFGF at a low concentration. Cell morphology and expression of CD146 and CD10 surface markers were analyzed using fluorescence microscopy. To measure mineralization, an alizarin red S assay was performed and typical markers of osteoblastic phenotype were evaluated by RT-PCR.

Results

EGF treatment induced morphological changes and suppression of CD146 and CD10 markers. Additionally, the cells were capable of producing calcium deposits and increasing the mRNA expression to alkaline phosphatase (ALP) and osteocalcin (OCN) in relation to control groups (p < 0.001). However, bFGF treatment showed an inhibitory effect.

Conclusion

These data suggests that DPSCs in combination with EGF could be an effective stem cell-based therapy for bone tissue engineering applications in periodontics and oral implantology.

Optimization of treatment with recombinant FGF-2 for proliferation and differentiation of human dental stem cells, mesenchymal stem cells, and osteoblasts

Basic fibroblast growth factor (bFGF or FGF-2) is widely used to modulate the proliferation and differentiation of certain cell types. An expression and purification system for recombinant human FGF-2 in Escherichia coli was established for the purpose of securing a continuous supply of this protein. The purified recombinant FGF-2 significantly increased the population of human embryonic stem cells. The optimal concentrations of FGF-2 for cell proliferative induction in various adult stem cells including human dental pulp stem cells, full term human periodontal ligament stem cells, human gingival fibroblasts, mesenchymal stem cells, and osteogenic oseosarcoma were established in a dose-dependent manner. When cells were treated with recombinant FGF-2 for 6 days before osteogenic induction, the mRNA expression of the bone markers was upregulated in cells originated from human dental pulp tissue, indicating that pretreatment with FGF-2 during culture increase stem cell/progenitor population and osteogenic potential.

Bone Marrow Mesenchymal Stem Cell Transplantation in a Rabbit Corneal Alkali Burn Model (A Histological and Immune Histo-chemical Study)

Background

Alkali-burned corneas can seldom heal properly to restore corneal transparency. Treatment of this severe disorder of the ocular surface remains a challenge.

Aim of the Work

was to investigate whether systemically transplanted bone marrow mesenchymal stem cells (BM-MSCs) can promote corneal wound healing after alkali burn.

Material and Methods

Thirty five male New Zealand rabbits were used in this study. The animals were divided into three groups. Group I; the control group was sham operated. Group II; corneal alkali burn was created. Group III; underwent corneal alkali burn then treated with BM-MSCs. All corneas were collected after fourteen and twenty eight days. Evaluation using H&E, PAS & alkaline phosphatase reaction was carried out. Immune histo-chemical staining for CD44 and vimentin was performed as well.

Results

the corneal epithelium of (Group II) showed marked alterations. Vascularization, cellular infiltration and irregularity of the collagen fibers were also seen in the substantia propria. Increase in the thickness of the Descemet’s membrane was noticed as well. On the other hand, at the time of 28 days, Group III rabbits showed best histological results with nearly healed corneas compared to other groups. Meanwhile, vimentin was more strongly expressed in Group III assessing the differentiating ability of BM-MSCs.

Conclusion

BM-MSCs could effectively promote corneal alkali burn healing.

Role of endogenous basic fibroblast growth factor in stem cells isolated from human exfoliated deciduous teeth

OBJECTIVE

This study aimed to investigate the role of endogenous basic fibroblast growth factor (bFGF) in stem cells isolated from human exfoliated deciduous teeth.

METHODS

Cells were isolated from dental pulp tissues of human exfoliated deciduous teeth. The expression of stem cell markers was determined using conventional semi-quantitative polymerase chain reaction (PCR) and flow cytometry. The multipotential differentiation ability was also examined. The lentiviral shRNA or fibroblast growth factor receptor (FGFR) inhibitor was employed to inhibit bFGF mRNA expression and signal transduction, respectively. The colony formation ability was determined by low-density cell seeding protocol. The mRNA expression was evaluated using real-time quantitative PCR. The osteogenic differentiation was examined using alkaline phosphatase enzymatic activity assay and alizarin red staining.

RESULTS

The results demonstrated that the cells isolated from human exfoliated deciduous teeth (SHEDs) exhibited stem cell characteristics, regarding marker expression and multipotential differentiation ability (osteogenic, adipogenic, and neurogenic lineage). The sh-bFGF transduced SHEDs had lower colony forming unit and higher mineralization than those of the control. Similarly, the decrease of colony number and the increase of mineral deposition were noted upon exposing cells to FGFR chemical inhibitor.

CONCLUSION

These results imply that the endogenous bFGF may participate in the colony formation and osteogenic differentiation ability. In addition, the inhibition of bFGF signalling may be useful to enhance osteogenic differentiation of stem cells.

Crucial role of Notch signaling in osteogenic differentiation of periodontal ligament stem cells in osteoporotic rats

Estrogen deficiency-induced osteoporosis typically occurs in postmenopausal women and has been strongly associated with periodontal diseases. Periodontal ligament stem cells (PDLSCs) isolated from the periodontal ligament can differentiate into many types of specialized cells, including osteoblast-like cells that contribute to periodontal tissue repair. The Notch signaling pathway is highly conserved and associated with self-renewal potential and cell-fate determination. Recently, several studies have focused on the relationship between Notch signaling and osteogenic differentiation. However, the precise mechanisms underlying this relationship are largely unknown. We have successfully isolated PDLSCs from both ovariectomized (OVX) and sham-operated rats. Both the mRNA and protein levels of Notch1 and Jagged1 were upregulated when PDLSCs were cultured in osteogenic induction media. Mineralization assays showed decreased calcium deposits in OVX-PDLSCs treated with a γ-secretase inhibitor compared with control cells. Thus Notch signaling is important in maintaining the osteogenic differentiation of PDLSCs in osteoporotic rats, which help in the development of a potential therapeutic strategy for periodontal disease in postmenopausal women.